1. Field of the Invention
The present invention relates to an object handling device for transferring objects such as semiconductor wafers.
2. Description of the Relevant Art
One known mechanism for transferring semiconductor wafers between the processing chamber of a plasma processing apparatus and a cassette which stores wafers is disclosed in Japanese Laid-Open Patent Publication No. 58-60552, for example.
The disclosed mechanism includes first and second feed means comprising belt conveyors which are located between the processing chamber and the cassette. The wafers stored in the cassette are brought one by one onto the belt conveyors, by which the wafers are delivered into the processing chamber. After the wafers have been processed, they are delivered out of the processing chamber and stored back into the cassette.
The conventional mechanism is however problematic in that the entire mechanism would become very complex if the direction of feed of the wafers between the processing chamber and the cassette were to change, and the reverse sides of the wafers are contaminated by dirt on the belt conveyors.